Neurosurgical procedures involve brain compression created by retractors. Although it is clear that retractors are causing
damage to the brain tissue, the pathophysiology of the retraction was not investigated in details. In the present study we
used the multiparametric monitoring approach for real time evaluation of mitochondrial function, hemodynamic, ionic
and electrical activities monitored contralaterally to the retractor placement on the brain. The aims of the study were to
test the effects of retractor size and severity of the compression on the degree of damage to the cerebral tissue.
A special probe was lowered towards the cerebral cortex, (2mm and 4mm in depth) using a micromanipulator.
Compression lasted for 30 minutes, than the retractor was elevated back to its initial position and monitoring continued
for two hours. Additionally, two sizes of retractors were used 6mm and 3mm in diameter, the 3mm retractor included an
intracranial pressure (ICP) probe.
The results show that the combination of a large retractor with the depth of 4mm yielded high mortality rate (62%) of the
rats while the use of a smaller retractor decreased significantly the percentage of mortality. Also, compression to the
depth of 4mm increased tissue injury as compared to 2mm depth.
In conclusion, the present study raises the importance and significance of multiparametric monitoring, and not only ICP
and cerebral blood flow of the areas nearby the retractor position and not only the retraction site, as well as the effect of
the retractor size on the damage induced to the cerebral tissue.